package com.cloud.alibaba.config.handler;

import com.alibaba.fastjson.JSON;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.web.reactive.error.ErrorWebExceptionHandler;
import org.springframework.cloud.gateway.support.NotFoundException;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.server.ResponseStatusException;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.util.HashMap;
import java.util.Map;

/**
 * 网关统一异常处理
 *
 * @author
 */
@Order(-1)
@Configuration
public class GatewayExceptionHandler implements ErrorWebExceptionHandler {
    private static final Logger log = LoggerFactory.getLogger(GatewayExceptionHandler.class);

    @Override
    public Mono<Void> handle(ServerWebExchange exchange, Throwable ex) {
        ServerHttpResponse response = exchange.getResponse();

        ResponseStatusException responseStatusException = null;

        if (exchange.getResponse().isCommitted()) {
            return Mono.error(ex);
        }

        String msg;

        if (ex instanceof NotFoundException) {
            msg = "服务未找到";
        } else if (ex instanceof ResponseStatusException) {
            responseStatusException = (ResponseStatusException) ex;
            msg = responseStatusException.getMessage();
        } else {
            msg = "内部服务器错误";
        }

        log.error("[网关异常处理]请求路径:{},异常信息:{}", exchange.getRequest().getPath(), ex.getMessage());

        response.getHeaders().setContentType(MediaType.APPLICATION_JSON);
        response.setStatusCode(HttpStatus.OK);

        if (responseStatusException != null) {
            ResponseStatusException finalResponseStatusException = responseStatusException;
            return response.writeWith(Mono.fromSupplier(() -> getDataBuffer(response, msg, finalResponseStatusException.getStatus().value())));
        } else {
            return response.writeWith(Mono.fromSupplier(() -> getDataBuffer(response, msg, 500)));
        }


    }

    private DataBuffer getDataBuffer(ServerHttpResponse response, String msg, int status) {
        DataBufferFactory bufferFactory = response.bufferFactory();
        Map<String, Object> map = new HashMap<>(2);
        map.put("status", status);
        map.put("msg", msg);
        return bufferFactory.wrap(JSON.toJSONBytes(map));
    }
}